Jaca, March 15, 2026. A study led by the Meteorological Service of Catalonia (METEOCAT), in collaboration with different institutions and linked to the LIFE Pyrenees4Clima project of the Pyrenean Climate Change Observatory (OPCC), analyzes the Pyrenees from a cross-border perspective and confirms that the air temperature continues to rise
as the years go by. Specifically, the region has lost three days of.

frost per decade (minimum temperature below 0°C) and has gained 4.9 summer days
per decade (days with a maximum temperature above 25°C). This means that the Pyrenees now have 20 fewer frost days than in 1959 and 32 more summer days over the same period. Likewise, the duration o
warm spells (consecutive days with an extremely high maximum temperature)
high) increases, while the duration of cold spells (consecutive days with a
low temperature) decreases.
temperatura mínima extremamente baja). “Actualizamos y analizamos cada año
unos indicadores climáticos concretos, dibujándose una clara tendencia hacia un
clima pirenaico más cálido en todo su conjunto y, en su vertiente sur, más
seco”, declara Jordi Cunillera, responsable del equipo de cambio climático del
Meteocat.

On the other hand, this increase in air temperature has also led to a
an increase in the water temperature of Pyrenean lakes. For example, in Ibón de Marboré (in the Aragonese Pyrenees), the surface water temperature (down to 5 m deep) has increased by almost half a degree over the last 10 years. “We are seeing an increase in lake heatwaves and a reduction in the period during which lakes are covered by ice, with changes in the water column that can cause episodes of anoxia, as already happened in Marboré in the winter of 2023–2024, a situation that seriously disrupts ecosystems,” explains Blas Valero, a researcher at IPE-CSIC who took part in the analysis.

Wildfire soot

The study also analyzes the evolution of aerosols and reveals that the presence
of Saharan dust and wildfire soot is increasing. Measurements taken at AEMET’s experimental field in Formigal-Sarrios recorded a peak in soot deposition of more than 5,000 ng/m³ during 2025, associated with the megafires in Castile and León and Galicia in the summer of the previous year. These data show the ability of particles to travel long distances and then be deposited in the Pyrenees, and they also show that in previous years they were detected following the fires in Canada. “These values reflect the growing impact of wildfires and the atmospheric transport of pollutants,” says Jorge Pey, also a researcher at IPE-CSIC. As for Saharan dust, it reaches the Pyrenees throughout the year, with occasional episodes of deposition of up to 20 g/m². Although in small amounts it fertilizes terrestrial and aquatic ecosystems, it is harmful to the duration of snow and ice in the mountains, since it alters the albedo of snow- and ice-covered surfaces, causing them to absorb energy instead of reflecting it.

Annual analysis
This study is presented in bulletin format and consists of an analysis of the main climate indicators in the Pyrenees to assess their evolution. The results are published annually in the Climate Change Indicators Bulletin.
of the Pyrenees Climate Change Indicators Bulletin (BICCPIR). This compilation and analysis form part of the key information supporting the adaptation process in the Pyrenees4Clima the LIFE project.
This project is coordinated by the Pyrenean Observatory of

Climate Change (OPCC), a cross-border initiative of the Working Community of
the Pyrenees (CTP). As for the data, they are based on the analysis of 12 temperature series and 26 precipitation series distributed across the entire mountain range and representing the climate of the whole massif. All the series cover the 1959–2024 period, and the reference period used to calculate anomalies is 1961–1990, except in the case of studies relating to snow, which use more recent series.

The contents and design of the BICCPIR bulletin were prepared by the Meteorological Service of Catalonia (Meteocat), which is a partner in the LIFE Pyrenees4Clima project and is responsible for the CLIMA working group, with contributions of data from Météo-France, the Meteorological Service of Andorra, AEMET, IPE-CSIC, the Basque Meteorology Agency (Euskalmet), and Meteocat itself.